The Oura Ring 4 is an advanced, comfortable smart ring designed for comprehensive health and wellness tracking, featuring a redesigned, slimmer form factor without internal sensor bumps, and enhanced Smart Sensing technology for improved accuracy in capturing heart rate, blood oxygen, sleep stages, and temperature trends. It offers in-depth data on sleep, activity, readiness, and stress, supported by a user-friendly app and a titanium build, providing insights into your physiological well-being